How come the robots like the T-600 T-800 or the T-850 never talk unless they have their synthetic skin on. These human skeleton looking robots scared the crap out of me more then any horror movie. I have never seen them talk unless they were covered up or had fake skin on why ?

I think its difficult to talk with no lips nor tongue. But in the fourth movie, the T-...600? does talk like a kid to lure Connor into an ambush, not wearing skin on nor anything, so probably they use a synthesizer instead of actually vocalizing.

What irks me more is why once they get to hand to hand combat with a human they don't just grab their victim by the neck and twist it like a chicken, instead of hurling them around again and again...

Probably so they can blend in, there isn't any real point to pretending to be human when you're a metal skeleton.

Maybe they learned hand-to-hand techniques by assimilating mankind's collection of horror movie cliches?

This. There is no reason for a terminator to speak at that point. They are cold , calculating machines that have one goal in mind.

They have very feminine voices and unfortunately it causes crippling shyness. One of the kinks we never got to work out before they went all genocidal, you see. Their own fault, really.

Maybe the whole genocide thing is an attempt to compensate.

At least they don't drive Hummers.

As stated earlier, the only reason for them to talk is to trick people into thinking they are human. If you are a giant, walking metal skeleton, then it kinda defeats the purpose.

I wanna say at the time the older terminators were made it was too hard to make them look like theyre talking?

Or was this directed in thr terminator story in general?